1. Technical Field
This invention relates to shut-off valves for controlling the flow of coolant liquid to several liquid cooled welding electrodes as used in robot welding applications and the like.
2. Description of the Prior Art
The automatic shut-off valve of the present invention operates when a substantial pressure difference occurs in a coolant supply line.
Prior art devices are disclosed is U.S. Pat. Nos. 1,775,773 and 3,431,375. The device of U.S. Pat. No. 1,775,773 incorporates a ball valve spring urged with respect to a valve seat, arranged to move an operating rod upon loss of pressure in the water line controlled, the operating rod directly actuating an electrical switch.
The U.S. Pat. No. 3,431,375 discloses a flow monitoring device that incorporates a valve with a by-pass around the valve and a piston movable in the by-pass for magnetically actuating a pressure indicating gauge. The valve comprises a valve element having a valve stem which may be adjustably positioned with respect to the valve seat. Neither of the devices of the U.S. Pat. Nos. 1,775,773 and 3,431,375 provide for the automatic action of dual fluid control valves acting to stop fluid flow through a controlled cooling circuit and the automatic valve upon the loss of pressure between the inlet and outlet ports of the valve such as occurs in the present invention.